Harvard Researchers Gather More Evidence Implicating Menthol in Health Disparities Between White and Black Smokers
For immediate release: August 18, 2005
Boston - In two papers appearing in the August 2005 issue of Nicotine & Tobacco Research, Harvard University researchers describe new evidence for the role of mentholated cigarettes in tobacco-related health disparities among White and Black smokers.
Menthol cigarettes make up approximately one quarter of the U.S. cigarette market and are smoked disproportionately by Black smokers with more than 70 percent of Black smokers using menthol cigarettes primarily. A new analysis of the amount of menthol in cigarettes across a sample of U.S. commercial brands shows significantly more added menthol to the tobacco in brands which are labeled as "light" or "ultralight." Researchers from Harvard School of Public Health (HSPH) said their findings suggest one important role of menthol may be to offset reductions in "tar" and nicotine delivery in so-called "light" cigarettes, either by replacing missing perceptions of strength or "impact" or by facilitating deeper inhalation than with regular cigarettes.
This study reports the first measures of cigarette menthol levels independent of internal industry studies. Recently, questions regarding the effects of menthol cigarettes have intensified as a result of noted health disparities among White and Black smokers. Although Blacks smoke fewer cigarettes per day than Whites, their health risk exposure may be higher as shown by greater risk for lung cancer, heart disease, and stroke. For example, Black male smokers have more than 30 percent higher risk of tobacco-related lung cancer than their White counterparts. Blacks also intake more nicotine per cigarette than Whites. Added menthol may play a role in the amount and degree of tobacco smoke inhaled and subsequent exposure to toxins
A second study by researchers from Harvard School of Dental Medicine (HSDM) examined the relationships among race, gender, menthol, and tobacco exposure measures, including cotinine (a chemical produced by the body from the nicotine in cigarettes that can be measured in saliva) among a group of 307 Boston-area smokers.
As expected, Blacks smoked less but had higher salivary cotinine levels (suggesting higher exposure to toxins) than Whites. However, the cotinine intake level for each cigarette (cotinine-cigarette ratio) varied by race, gender and cigarette type, menthol or non-menthol. The ratio was the highest among Black menthol smokers, although Black women smoking non-menthol cigarettes also had high values.
The authors believe that more extensive research needs to be done to understand the differences between race, gender, type of cigarette and cotinine levels, as well as the potential connection between cotinine levels and smoking related diseases.
Said HSPH co-author Gregory N. Connolly, professor of public health practice and director of HSPH's Tobacco Control Research Program: "These studies contribute to a growing body of evidence demonstrating the role of menthol in disease risk among African Americans, as well as reinforcing addiction, making quitting more difficult. The findings may ultimately help to explain the disproportionate health impact of smoking among Black smokers and the role of additives in promoting addiction. This should raise concerns as to why the use of menthol and other cigarette additives remains unregulated."
The HSPH authors cite an analysis of tobacco industry documents which described internal industry research on the use and effects of menthol, confirming the influence of menthol on perceptions of cigarette smoke strength or "impact" and suggesting a number of physiological effects including menthol's characteristic "cooling" effect, stimulation of nerves in the mouth and throat, anesthetic effect on the lung, enhanced absorption of other smoke constituents and altered respiratory patterns, including deeper inhalation.
The HSPH authors note that tobacco manufacturers are more likely to advertise mentholated brands in areas with disproportionately higher minority populations, to feature non-White models in advertisements for mentholated cigarettes and to advertise mentholated cigarettes in magazines with higher minority readerships.
"Although smokers may believe that the term 'light' implies a reduction in disease risk, this is not true, and menthol may be playing an important role in this misperception," said Connolly. "The present findings suggest the need for further examination of the role of additives such as menthol, particularly in cigarettes claiming or implying reduced delivery."
HSDM researchers suggest that the relationship between number of cigarettes consumed and the level of salivary cotinine, often used to help understand and measure patients' exposure to cigarette toxins and their success at quitting, is more complex than previously believed. Researchers and clinicians need to look at the combination of race, gender and type of cigarette consumed, particularly menthol cigarettes, to understand tobacco exposure and disease risk.
"It is well established that Black smokers metabolize cotinine more slowly than do Whites," said Taru Kinnunen Mustonen, PhD, leader of the HSDM study. "Together with the menthol's added effects, this could explain the higher cotinine-cigarette ratio among blacks. Cigarettes per day is the most commonly used estimate of disease risk at the doctor's office. The current results suggest that health-risk exposure assessment should go beyond the daily numbers and consider the race, gender and type of cigarettes as well."
"More information like the HSPH study considering cigarettes' ingredients and their effects on nicotine and other substances in tobacco smoke is needed," said Kinnunen Mustonen, an assistant professor of oral health policy and epidemiology at HSDM.
Funding for the HSPH research was provided by the National Cancer Institute. Funding for the HSDM research was provided by the National Institute on Drug Abuse.
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HARVARD SCHOOL OF DENTAL MEDICINE
Harvard School of Dental Medicine (HSDM) is the oldest university-affiliated dental school in the nation and is committed to educating leaders in dental health. HSDM's mission is to produce leaders who advance knowledge and discovery, serve the community through patient care and advocacy, and contribute to improved oral health and the quality of life. The school offers a unique problem-based learning pre-doctoral curriculum, as well as specialized advanced graduate education programs. HSDM also has a strong interdisciplinary research program.